Reinforcing patch plate applied to liquid passage hole in filter-surfaced expressing sheet on expressing filter plate

Abstract

A reinforcing patch plate comprises a boss portion adapted to be fitted in a liquid passage hole, such as one for filtrate or wash liquor, which is open to a filter surface of a filter-surfaced expressing sheet, a liquid guiding flange portion integrally formed on one end of the boss portion to cover the portion of the expressing sheet around the liquid passage hole, and a core embedded therein to serve as an intermediate layer. The liquid guiding flange is provided on its face with liquid guiding outlet grooves which establish communication between the boss portion and the filtrate grooves of the filter surface of the expressing sheet. The liquid guide grooves are each defined between adjacent ridges arranged side by side on the flange portion and removably attached to the latter.

What is claimed is: 
     
       1. In a liquid passage reinforcing patch plate for use with an expressing sheet of flexible fluid-tight material, such as rubber, which separates the prefilt chamber and the expressing fluid chamber from each other and which is formed with an irregular filter surface opposed to the prefilt chamber and is adapted to bulge toward the prefilt chamber upon completion of filtration so as to press the cake, said patch plate being mounted in a liquid passage hole, such as a filtrate outlet hole or wash liquor introducing hole, which is open to said filter surface, said patch plate having a boss portion adapted to be fitted in said liquid passage hole and a liquid guiding flange portion integrally formed at one end of said boss portion to cover the portion of the expressing sheet around said liquid passage hole in the sheet, said boss and flange portions being made of a material whose hardness is equal to or somewhat greater than the expressing sheet, said liquid guiding flange portion being formed on its surface with liquid buiding grooves establishing communication between the liquid guiding grooves of the expressing sheet surface and said boss portion, the improvement comprising said boss and flange portions being of laminated construction wherein a core serving as a reinforcing intermediate layer is interposed between a front layer and a back layer which are integrated with the core. 
     
     
       2. A liquid passage reinforcing patch plate as set forth in claim 1, wherein the boss and flange portions of said patch plate are made of urethane rubber or other rubber or plastic. 
     
     
       3. A liquid passage reinforcing patch plate as set forth in claim 1, wherein said core is made of metal, rigid plastic or fiberglass reinforced plastic. 
     
     
       4. A liquid passage reinforcing patch plate as set forth in claim 1, wherein said core is embedded in the patch plate by means of the insert-molding of the boss and flange portions of the patch plate. 
     
     
       5. A liquid passage hole reinforcing patch plate as set forth in claim 1, wherein said core is joined to the front and back layers of the patch plate by mechanical fastening means, such as rivets and screws. 
     
     
       6. A liquid passage hole reinforcing patch plate as set forth in claim 1, wherein said core is joined to the front and back layers of the patch plate by means of bonding or welding. 
     
     
       7. A liquid passage hole reinforcing patch plate as set forth in claim 6, wherein mechanical fastening means, such as rivets, is jointly used in said joining of the core to the front and back layers of the patch plate. 
     
     
       8. A liquid passage hole reinforcing patch plate as set forth in claim 1, wherein the core has holes at a suitable number of places and is welded to the front and back layers of the patch plate. 
     
     
       9. A liquid passage hole reinforcing patch plate as set forth in claim 1 wherein the liquid guiding grooves of the liquid guiding flange portion are each defined between adjacent ridges arranged side by side on the surface of the flange portion, said ridges being removably attached to the flange portion by having dovetail base portions interengaging in dovetail grooves formed in the surface of the flange portion and extending through said core.